Thaddeus cahill



UNITED STATES PATENT OFFICE.

THADDEUS OAHILL, OF OBERLIN, OHIO, ASSIGNOB OF TWO-THIRDS TO TIMOTHY OAHILL, OF SAME PLACE.

WANG-ACTION.

SPECIFICATION forming part of Letters Patent No. 359,557, dated March 15, 1887.

Application filed November 16, 1886. Serial No. 219,002. (No model.)

.To ctZZ whom it may concern.-

Be it known that I, THADDEUS CAHILL, a citizen of the United States, residing at Oberlin, in the county of Lorain and State of Ohio, have invented a new and useful Improvement "in Piano-Forte Actions, of which the following is a specification.

My invention, though applicable to many forms of action, is designed for and relates more especially to that class of piano-forte actions in which a touch-varying resistance is opposed to the retreat of the hammer from the string by the arresting of the finger-key through the intervention of the ham mer-butt. These actions are shown in Figs. 4, 5, 6, 11, 12, 13, and 14 of the drawings of an application for Letters Patent filed by me on May 27, 1886, Serial No. 203,370, in which application they are described at length. In them the hammer-butt and hammer are subjected to said touch-varying resistance for a certain fraction of their tone-producing motion, and the tone is in consequence somewhat weakened.

The objectof my present invention is to overcome this defect; and my invention consists in the combination of the key or other part which actuates the hammer with a suitable movable mass or with suitable movable masses so constructed and arranged that the key or other similar actuating part, near the limit of its tone-producing motion or excursion, comes in contact with andimparts a con siderable portion of its moving force to said movable mass or masses, and thereby reduces its own velocityto such an extent as to permit the hammer to pass toward the string, or even against it, and begin its retreat therefrom before the key is arrested through the intervention of the hammer-butt and a touch varying resistance is opposed to the retreat of the hammer.

For the sake of convenience, Ishall call the movable masses mentioned key-retarding masses, and the levers and other parts thus used I shall limit by the same adjective.

Each key of the instrument may have its own kcy retarding mass or 1nasses,or a greater number of the keys may have the same keyretarding mass or masses. I have preferred, for obvious reasons, to have two keys operate anism presses upon, and is arrested by or I through the intervention of a hammer-butt which has that part upon which the key presses substantially circular or arc-like in outline, so that its rotary or angular motion, when pressed upon by the key, cannot disturb the vertical position of the part last named.

Figures 1 and 2show a piano-key and a keyretarding lever upon which said key acts directly. Figs. 3 and 1 show a piano-key and key-retarding lever and a multiplying-lever for transmitting motion from the piano-key to the key-retarding lever and for magnifying the motion of the key to insure its acting upon the keyretarding lever before it is arrested through the intervention of the hammer-butt.

Figs. 5 and 6 showapianokey acting directly upon a key-retarding lever which is arrested through the intervention of the hammer-butt, the key being first retarded by the key-retarding lever, and then arrested by the hammerbutt through the intervention of the key-1e tarding lever. Fig. 7 shows a piano-key which actuates the hammer not directly, but through intervening mechanisn1,wliich latter acts upon the key-retarding mass. Figs. 1, 8, 5, and 7 show the parts in their normal positions, and Figs. 2, 4:, and 6 show them in the positions they assume when the key is held down; and Figs. 8, 9, 10, and 11 are end sections on the linesx 00in Figs. 1, 3, 5, and 7-the corresponding views-of two keys and theirkeyretarding mechanism.

In the drawings, A represents a piano-key, centered by a pin, a, driven into a bar, a, which is secured to the key-frame of the instru ment at suitablepoints,and elevated thercfrom a sufficient distance to give room for the key-retarding mechanism when this is placed below the keys, as shown in the first four figures.

5 b is the multiplying-lever, centered byapin,

b, driven into a bar, If, which is suitably attached to the frame-work.

c is the key-retarding lever, centered by a pin, 0', driven into a bar a which latter is suitably attached to the frame-work of the instrument.

(I is a metal weight placed as a balance upon the shorter arm of the multiplying-lever b or key-retarding lever c.

c is an upright piece for transmitting motion from the key A to an auxiliary lever, f, which latter communicates it, by the transmitter g, to the hammer-butt h and hammer i.

j and 7; are felted bars placed, respectively, under the different ends of the levers, upon the former of which said levers normally rest.

Z refers to a screw and lock nut placed in the bar j for regulating at what fraction of the depression of the key it shall begin to move the key'reta-rding mass or masses.

The operation of the devices shown for carrying out my invention is as follows: Thekey A, during the former and greater part of its tone-producing motion or excursion, (say, for

0 instance, from seven-eighths to twenty-three twenty-fourths of its tone-producing excur sion) throws the hammer toward the string and moves with a gradually-increasing velocity; but near the end of its tone-producing excursion it communicates a large part of its moving force to the key-retardinglever. This it does either directly, as shown in Figs. 1, 2, 4, and 6, or through suitable connecting mechanism, as the multiplying-levershown in Figs.

0 3 and 4 or the upright piece and auxiliary lever shown in Fig. 7. As aresult of this impart-ation of motion from the key, near the end of its tone-producing excursion, to the keyretarding mechanism, the velocity of the former 5 during the remaining part of its motion is very greatly reduced, and in consequence the hammer has time to reach the string before its motion is hindered by thetouch-varying pressure caused by the arresting of the key through the intervention of the hammer-butt, with which the key, at the end of its downward or tone-producing motion or excursion, comes in direct contact, as shown in Figs. 1, 2, 8,and 4, or upon which it presses through suitable 5 5 intervening mechanism, as shown in Figs. 5,

' 6, and 7. r

The mass of the key-retarding lever with relation to that of the key and the displacement of the former by a given motion-of the latter necessary to retard the key or to reduce its velocity to any particular desired extent can be determined according to the well-known laws of motion. But, not only on account of the action of the key upon the key-retarding mechanism,but also on account of the blow of the key-retarding mechanism when returning to its normal position against the depressed key, I prefer to employ a small mass-as, for instance, one equal to or less than that of the key-whicl1, through the impact of the key, is moved through a large space, rather than a great mass moved through a small space; for, according to a well-known law of motion, the opposite momenta generated by the impact of two bodies are equal, no matter what their relative masses may be. New, momentum is the product of mass and velocity simply, and if the key-retarding mass be lighter than the key, and have, as we have seen, the same momentum as that of opposite sign or direction that appears in thekey as aresult of its action upon the key-retarding mechanism, or as the reaction to that action, itmust have a greater velocity, and since absolute energy or the power to perform work is not merely the product of mass and velocity simply, but is the product of the mass by the square of the velocity, it follows, as a particular case under a universal law, that in all impacts of the key and key-retarding mass the absolute force which appears in the key-retarding mass as a result of the impact is as much greater than that which appears in the key as the mass of the key is greater than that of the key-retarding mass. Itis on this account that I so construct and arrange the key and key-retarding mechanism, as shown in the drawings, that the key acts upon the former near its center of motion, and so gives to the key-retarding lever a very much greater angular velocity and a much greater absolute velocity than it itself possesses.

Of course springs may be used to return the various parts to their normal positions, (shown in Figs. 1, 3, 5, and 7;) but I prefer to so balance and weight them that they can return to their normal positions without external assistance.

I show in the accompanying drawings several different forms of mechanism by which my invention may be carried out; but I do not by any means show all of the many forms and arrangements of mechanism that may be used for this purpose. Thus, for-instance, the multiplying-lever 1) (shown in Figs. 3 and 4) can be used when it is deemed desirable in actions in which, as in that shown in Figs. 5 and 6, that motion of the key-retarding lever which it receives from the key near the limit of its tone-producing excursion is arrested by the hammer-butt, and in actions in which, as in that shown in Fig. 7, the key acts through intervening mechanism upon the hammerbutt and key-retarding mass, both of which are at a distance from it; and in those actions in which, as in Fig. 7, the key-retarding lever and the hammer-butt are at a distance from the key the key-retarding lever may be arrested through the intervention of the hammer-butt when it is deemed desirable; and in down-striking actions and in all cases where it is deemed desirable the relative vertical positions of the key and the key-retarding mechanism, as shown in the drawings, may

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of course be inverted; and in grand pianos, where there is room for it, the key-retarding lever, instead of being placed below the keys, as shown in .Figs. 1, 2, 3, and 4, or above them, as shown in Figs. 5 and6, may be placed back of them when it is deemed desirable.

I have shown for each key or for each pair of keys a single simple straight lever as the key-retarding mass, because I consider it to be in every way the simplest, cheapest, and best; but a system of two or more levers, each of which is acted upon by the preceding lever and in turn acts upon the succeeding lever, may be used, if it is deemed desirable, in place of the single lever shown; and abentlever, or a bell-crank lever, or a wheel, which is a re volving lever, or any other suitable mass properly arranged, may be made to embody my invention, and to be, in the combinations hereinafter claimed, the equivalent of the simple straight lever shown. Therefore I do not limit myself in the carrying out of my invention to the details of mechanism herein described, for my invention does not consist, solely, in particular key retarding mechanism, but, more broadly, in the combination of the key or other part which actuates the hammer with a suitable movable mass or with suitable movable masses so constructed and arranged that said key or other actuating part, near the limit of its tone-producing motion, comes in contactwith the movable mass directly or through intervening mechanism presses upon the matter that constitutes the key-retarding mass and setsit in motion, and suddenly imparts to said movable mass or masses a considerable part of its momentum, and so reduces its own velocity. Nor do Ilimit myself to applying this invention to the action described in my beforementioned application for Letters Patent, as I am aware that it is also applicable to other piano-actions. It may, for instance, be used with great advantage in such actions as those described in English Patent No. 905 of A. D. 1856 to Frederick Priestley. It may also be used, ifso desired, in connection with a back-catch or back-check, without an escapement device,asasubstitute for such escapement device, where it is now the universal practiceto use an escapement device, for in piano-forte actions as generally constructed the key, by means of a jack, hopper, flier, or similar es capement device, which engages in a notch in the hammenbutt, throws the hammer during the greater part of its .toneproducing excursion toward the string; but near the end of its tone-producing excursion the jack, hopper, flier, or similar escapement device moves or is moved out of the notch before mentioned, and the hammer, no longer impelled by the key, moves on by virtue of its acquired momentum toward the string and away from and beyond the point at which it ceased to be impelled by the key, and so leaves time and space for the key, which meanwhile also moves on through the remaining portion of its tone-producing excursion, to move a suitable back-catch or back-check into such a position that when the hammer, after striking the stri ng, rebounds from it, it wedges and packs and catches or is caught upon or by the backcatch or back-cheek thus moved into position. Now, with a key-retarding mass combined with the key, as shown, for instance, in Figs. 1, 2, 3, and 4, thejack, hopper, flier, or similar escapement device part of the time engages in the notch, so that any motion of the key produces a corresponding motion of the hammer, and part of the time is out of the notch, so that the key cannot move the hammer in the least until it has first moved into such a position that the jack, hopper, or flier again enters the notch. This escapement device and its indispensable springs or straps and jack-button orjack-check, and other auxiliary contrivances, which are well known to be among the most delicate parts of that very delicate mechanism-a piano-forte actionand which are amongthe first to wear, to require adjustment, to get out of order, and to block, and to be injuriously affected by moisture and dampness, may, as I have said, be dispensed with, and the key may throw the hammer toward the string directly, or, as shown, for instance, in Figs. 1, 2, 3, 4:, 5, and 6, by means of a piece-such, for instance, as that shown in the drawings and marked g-rigidly attached to it, or by any other suitable transmitting contrivance-such, for instance, as that shown in Fig. 7, which is connected directly with the key, and is always in position to act upon the hammer-butt or hammer-shank and to throw the hammer toward the string-for when in this case the key, while throwing the hammer toward the string, comes in contact with the key-retarding mass the velocity of that part of the key which acts upon the hammer-butt or hammershank becomes less than the velocity of that part of the hammer-butt or hanimer shank upon which it acts, and the hammer, no longer impelled by the key, moves on by virtue of its acquired momentum toward the string and away from and beyond the point at which it ceased to beimpelled by the key, andso leaves time and space for the now slowly-moving key to traverse the small remainder of its toneprodncing excursion and to move a suitable back-catch or backcheck into a suitable position,so that when the hammenafter striking the string rebounds from it, it wedges and packs and catches or is caught upon or by the back-catch or back-chcck thus moved into position. Scores,ifnothundreds,ofbackcheck or back-catch devices have been patented. Very many such devices are known in the art, and some form of back-check or back-catch is to be found in almost every piano,.if not in every piano. I do not therefore consider it necessary to describe the application of my inventionin connection with sucha device at greater length, nor to represent it by drawings, and the more especially as my invention does not consist in any sort of a catch or check, but in retarding the motion and reducing the velocity of the key near the end of its tone-producing motion. For this purpose I have described several mechanisms, of which that shown in Figs. 1 and 2 and that shown in Figs. 8 and 4: may be used for retarding the toneproducing motion of the key in all cases, however the other parts of the action may be constructed. I have thus described the application of a key- 1 retarding device to an action in which the key,

without an eseapement device, throws the hammer toward the string,and then has its motion retarded, and so has time to move and does move a catch or check into position to catch and hold the hammer on its rebound from the strings, not because I consider it by any means so good an action as that shown in the draw ings, in which the checking etfect is produced by the touch-varying pressure ofthe key upon the hammer-butt, by or through the intervention ofwhich its tone-producing excursion is stopped, defined, and limited, but that it may be clearly seen that my invention may be applied to many forms of action.

I wish it to be understood that when I claim, as I do hereinafter, the combination of apiano key with key-retarding mechanism, I refer to, include, and cover such a combination both when the key itselt'aets directly upon the keyretarding mechanism, as shown, for instance, in Figs. 1, 2, 5, and 6, and when it acts upon the key-retarding mass through suitable connecting and intervening mcchanismas, for instance, that shown in Figs. 8,4, and 7. And I also wish it to be understood that when I claim, as I do hereinafter, the combination of a piano-key and key-retarding mechanism with a hammer-butt with which the key comes in contact or upon which it acts, I refer to,include,and cover such a combination both when the key itself comes in contact with the hammer-butt directly, as shown, for instance, in Figs. 1, 2, 3, and 1-, and when it acts upon it through any suitable intervening mechanism as, for instance, that shown in Figs; 5 and 6 or that shown in Fig. 7. And I wish it to be understood that Ido not claim, broadly, the combination of a piano-key with a lever, whatever function it may perform and whatever mode of operation it may be made to embody.

Although I show in Figs. 1, 2, 8, and at of the drawings accompanying this application the direct combination of a piano-forte key with a hammer-butt having a substantially circular or are-like outline, and so arranged that the key, at the end of its tone-producing excursion, comes in direct contact with the curved or arc-like side surface or part of the said hammer-butt, which limits its tone-producing excursion and upon which it exerts a touch-varying frictional resistance to angular motion, I do not claim the said combination in this application, for it forms a part of the subject-matter of an application for Letters Patent filed by me in the United States Patent Ofliee on May 27,1886, Serial No. 208,370,

and is clearly shown in Figs. 11, 12, 13, and 14 of the drawings accompanying the said application, as also in Figs. 1, 2, 3, and 4 of the drawings accompanying an application filed by me October 17, 1885, Serial No. 180,208, allowed May 13, 1886, of which latter application that of May 27, 1886, is a continuation. It will be understood, therefore, that this present application is intended to cover those combinations in which a key-retarding lever or similar keyretarding mass is an element, and those only.

Vhat, therefore, I do claim as my own, and desire to secure by Letters Patent, is

1. In a pianoforte action, the combination, substantially as hereinbefore described, of a piano-key with a key-retarding lever or similar key-retarding mass arranged with relation to the key in such a manner that said key, near the limit of its tone-producing excursion, comes in direct contact with, or through intervening mechanism presses upon, the keyretarding mass and sets it in motion, substantially as hereinbei'ore described, for the purpose set forth.

2. In a piano forte action, the combination, substantially as described, ot a hammer-butt and a piano-key so arranged thatit, at or near the limit of its (the keys) tone-producing excursion, comes in contact with, or through intervening mechanism presses upon,said hammerbutt and checks and hinders its motion, with a key-retarding lever or similar keyretarding mass arranged with relation to the beforenientioned key in such a manner that said key, near the limit of its tone-producing excursion, comes in contact with, or through intervening mechanism presses upon,thebefore-mentioned key-retarding mass and sets it in motion, substantially as hereinbefore described, for the purpose set forth.

8. In a piano-forte action, the combination, substantially as hereinbelbre described, of a hammer-butt and a piano-key so constructed and arranged that it, at or near the limit of its (the k eys) toneproducing excursion, comes in contact with, or through intervening mechanism presses upon, said hammer-butt and has its tonei roducin g excursion or motion stopped and limited by or through the intervention of said hammer-butt, upon which it exerts a touclrvarying pressure, with a key-retarding lover or similar key-retarding mass arranged with relation to said key in such a manner that said key, near the limit of its tone-pro ducing excursion, comes in contact with, or through intervening mechanism presses upon, the before-mentioned key-retardingmass and sets it in motion, substantially as hereinbefore described, for the purpose set forth.

t. In a piano-forte action, the combination, substantially as hercinbei'ore described, of a hammer butt which has that part against which the key presses substantially circular or arc-like in outline, so that its rotary or angular motion, when pressed upon by the key, cannot materially disturb the vertical position ICC of said key, and a piano-key so constructed mass arranged with relation to the before and arranged that it, at the end of its tonementioned key in such a manner that said key, producing excursion, comes in contact with,or near the limit of its tone-producing excursion, I 5 through intervening mechanism presses upon, comes in contact with, or through intervening 5 said hammer-butt and has its tone-producing mechanism presses upon, said key-retarding excursion stopped, limited, and defined by or mass and sets it in motion, substantially as through the intervention of said hammer-butt, hereinbefore described, for the purpose set upon which it exerts a touch-varying pressure forth.

and a consequent touch-varying frictional re- THADDEUS OAHILL. 1o sistance to its angular motion and to the re- Vitnesses:

treat of the hammer from the string, with a F. J. \VILLIs,

key-retarding lever or similar key-retarding W. L. BIURPHY; 

